This invention relates to control devices for small motors, and to methods for manufacture and assembly thereof. The field of application of this invention is particularly, but not solely, related to an electric motor for operating such servomechanisms as may equip a vehicle, and reference to that field will be made in the following description for convenience of illustration.
Electric motors are utilized in ever increasing number on modern vehicles for operating a range of servomechanisms, such as power windows, power seats, heating/air-conditioning system controls, self-locking doors, aerial drives, etc. Such motors must be powered under control by some specific electric and electronic components of a passive type (resistors and capacitors) as well as an active type (an integrated circuit).
To this aim, a printed circuit is usually provided to carry the necessary passive and active components. The printed circuit is first mounted onto an insulating holder, and then connected electrically to the motor by fitting purposely provided female connectors thereof over projecting leads (electrically active studs) from the motor. The female connectors are simple through holes formed in the printed circuit board. The printed circuit board may be provided with deformable lugs for retaining the leads securely therein after their insertion. In addition, a multiple connector is normally attached to the printed circuit, so that connection can be made to power and control wiring. Accordingly, assembly of the motor tends to be an awkward operation.
The underlying problem of this invention is, therefore, to provide for simpler assembly of an electric motor for vehicular applications. This problem is solved, according to the invention, by a control interface device which includes an integrated circuit encapsulated in a single solid body, which has apertures (e.g. through holes) in it for mounting on the motor leads, and which also has a standard connector interface extending out from the body, for attachment of a standard wiring connector to provide power and signal connections. In this way, all of the required elements for powering and controlling the motor can be contained within a single enclosing body which is more convenient to handle and connect.
Thus, the electric connectors of the solid body preferably include male connectors for connection to power and control wires, and female connectors for connection to the motor. The enclosing body will preferably include alignment pins, formed integrally at locations proximate to the male connectors, which serve to ensure a correct and secure mechanical coupling to the power and control wires.
Preferably, the enclosing body is injection molded around the active component on a lead frame, and the waste portions of the lead frame are later sheared off.
According to one class of innovative embodiments, there is provided: a control interface device for an electronic motor, comprising: a plurality of leads formed of a common conductive material, and sharing a substantially common plane; an integrated circuit mounted on at least one of the leads, and electrically connected to others of the leads; an enclosing body of an electrically insulative material which surrounds the integrated circuit and at least a portion of each the lead; the body including through-holes therein which pass through the body, in a direction substantially normal to the plane, and which abut one of the leads therein; some ones of the leads extending out of the body to provide a plurality of parallel electromechanical connectors.
According to another class of innovative embodiments, there is provided: an electronic motor assembly, comprising: a housing which encloses a motor and which has an aperture therein with substantially rigid studs protruding through the aperture to provide electrical connection to the motor; and a plurality of leads formed of a common conductive material, and sharing a substantially common plane; an integrated circuit mounted on at least one of the leads, and electrically connected to others of the leads; an enclosing body of an electrically insulative material which surrounds the integrated circuit and at least a portion of each the lead; the body including apertures therein which provide openings into the body in a direction substantially normal to the plane, and which abut one of the leads therein; some ones of the leads extending out of the body to provide a plurality of parallel electromechanical connectors.
According to another class of innovative embodiments, there is provided: a method of assembling an electronic motor assembly, comprising the steps of: providing a housing which encloses a motor and which has an aperture therein with substantially rigid studs protruding through the aperture to provide electrical connection to the motor; inserting, onto the studs, a solid control module which includes at least one integrated circuit encapsulated therein, and which has apertures therein in a pattern which generally corresponds to the studs, and including concealed internal electrical connections to at least some of the apertures; the solid control module also having lateral connectors, which are normal to the studs; and inserting a connector, onto the lateral connectors of the solid encapsulated control module, to provide power, signal, and ground connections.
According to another class of innovative embodiments, there is provided: a fabrication method, comprising the steps of: forming a frame from a sheet of conductive material, the frame having electromechanical connectors integral with the body of the frame; mechanically securing an integrated circuit to the frame and establishing electrical links as needed; using an injection molding process to form an enclosing body of an electrically insulating material over the frame and the integrated circuit together, the enclosing body including through-holes therein which pass through the body, in a direction substantially normal to the frame, and which adjoin ones of the leads within the body; and removing waste portions of the frame, to define electrically separate leads which are connected to different respective portions of the integrated circuit.
Further features and advantages of a control interface device according to the invention will become more clearly apparent from the following description of a preferred embodiment thereof, to be read in conjunction with the accompanying drawings.